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CHAPTER 1
INTRODUCTION
1.1 Background
Nanoscience is an exciting field of study that brought us into nanomaterials exploration. The prefix nano means one-billionth of something like a meter or a second, in
comparison 1 nm is 10000 times smaller than the average diameter of a human hair. In principle, nanomaterials are described as materials with at least one external dimension in the
nanometer length scale of 1-100 nm. The exploitation of novel phenomena and properties of nanomaterials can enable ground-breaking, as opposed to conventional, advances in science
and technology that offer the tools to understand and control how materials are made at the atomic and molecular level. The understandability and controllability at this level could open
new paths to create new materials that subsequently leads to developing new devices are unlimited Rao et al., 2005.
Generally, utmost significant impact in this field was triggered by a breakthrough in nanomaterial synthesis. Therefore, tremendous effort in material syntheses are being
enthusiastically conducted by researchers and scientists globally to achieve the rational approaches that regarded as the vital point to successfully synthesizes new materials.
Nonetheless it is still far from done, these nanomaterials essentially need to be assembled hierarchically and developed into complex and functional architectural elements for devices
and applications. The explorations in hierarchical assembly of nanomaterials enable the
2 development of architectural elements that have innovative and rational structures and
functions, in addition to perceive their fundamental properties Jariwala et al., 2013. Unfortunately, in numerous occasions the unique fundamental properties are yet to be known,
thus the possible applications are also unknown. In recent decades, carbon nanomaterials have been the hot topic in nanoscience and
nanotechnology field due to their extraordinary electrical, thermal, mechanical and chemical properties and have the supreme potential to be utilized as energy storage and conversion,
composite materials, field emission devices, drug delivery, sensors and nanoscale electronic components O’Connel, 2006. Carbon nanomaterials are nanostructure composed of carbon
atoms and have more than one form, from 0-D to 3-D. One of the most well-known carbon nanomaterials is carbon nanotube CNT and was first reported in literature by Baker et al.
1972, 1973 but termed as filamentous carbon. These reports did not simulate the interest of the research on CNT but only the mechanism for filament growth. The real breakthrough came
almost 20 years later with the experimental observation of CNTs in 1991 by Iijima using high- resolution transmission electron microscopy HR-TEM Iijima, 1991. Since that, the studies
on CNTs grew rapidly due to the unique structures and properties of CNTs. The rapid advancement in the field of nanoscience and nanotechnology with the need
for commercialization of CNTs product at large-scale has led the necessity to develop efficient growth techniques. Various techniques have been developed to growth CNTs including arc
discharge, laser ablation, and chemical vapor deposition CVD. Among these techniques, CVD using alcohol as carbon feedstock known as alcohol catalytic chemical vapor deposition
AC-CVD is among the promising technique to grow CNTs Murakami et al., 2003a which is well known for its economical merit, wide selectivity of substrates, better catalytic reaction,
and ability to grow high purity CNTs. CNTs especially aligned CNTs A-CNTs have
3 numerous potential applications in nanoelectronics, field emission devices, and biological
probes, among others. Thus in order to accomplish CNTs full potential, better understanding on the CNT growth become essential for those who working in this area.
1.2 Problem statement
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